Add task to verify a release.

Basically revises the release flow to:

* Update the version in RAILS_VERSION + rake changelog:header
* Run rake all:verify (click around in the booted app)
* If that checks out, run rake release.

Rakefile

@@ -7,6 +7,9 @@ require "railties/lib/rails/api/task"
 desc "Build gem files for all projects"
 task build: "all:build"
 
+desc "Build, install and verify the gem files in a generated Rails app."
+task verify: "all:verify"
+
 desc "Prepare the release"
 task prep_release: "all:prep_release"
 

tasks/release.rb

@@ -142,7 +142,7 @@
   task push: FRAMEWORKS.map { |f| "#{f}:push"            } + ["rails:push"]
 
   task :ensure_clean_state do
-    unless `git status -s | grep -v 'RAILS_VERSION\\|CHANGELOG\\|Gemfile.lock\\|package.json\\|version.rb'`.strip.empty?
+    unless `git status -s | grep -v 'RAILS_VERSION\\|CHANGELOG\\|Gemfile.lock\\|package.json\\|version.rb\\|tasks/release.rb'`.strip.empty?
       abort "[ABORTING] `git status` reports a dirty tree. Make sure all changes are committed"
     end
 
@@ -152,6 +152,27 @@
     end
   end
 
+  task verify: :install do
+    app_name = "pkg/verify-#{version}-#{Time.now.to_i}"
+    sh "rails new #{app_name}"
+    cd app_name
+    sh "rails generate scaffold user name admin:boolean && rails db:migrate"
+
+    puts "Booting a Rails server. Verify the release by:"
+    puts
+    puts "- Seeing the correct release number on the root page"
+    puts "- Viewing /users"
+    puts "- Creating a user"
+    puts "- Updating a user (e.g. disable the admin flag)"
+    puts "- Deleting a user on /users"
+    puts "- Whatever else you want."
+    begin
+      sh "rails server"
+    rescue Interrupt
+      # Server passes along interrupt. Prevent halting verify task.
+    end
+  end
+
   task :bundle do
     sh "bundle check"
   end